Extracorporeal membrane oxygenation as a bridge to lung transplantation: what lessons might we learn from volume and...

We sought to evaluate the effect of centre volume on survival when extracorporeal membrane oxygenation (ECMO) is used as a bridge to lung transplantation (LTx).

We performed a retrospective analysis of the United Network for Organ Sharing data on adult lung transplantations performed between 2000 and 2014. Centres were categorized based on volume of transplants into low-, medium- and high-volume centres (1-5, 6-15 and >15, respectively). Baseline characteristics were assessed and a Kaplan-Meier analysis was used to estimate survival with log-rank test. We used multivariate Cox regression analysis to estimate the risk of post-transplant 1-year mortality between centres.

A total of 342 adult recipients were bridged on ECMO. Of these recipients, 88 (25.7%) were bridged in low, 89 (26%) in medium and 165 (48.2%) in high-volume centres. Patients in medium-volume centres were more likely to be older compared with those in low-volume and high-volume centres with a median age of 56, 46 and 49 years, respectively. High-volume centres reported the highest proportion (94.6%) of bilateral lung recipients, followed by low-volume (86.4%) and medium-volume centres (77.5%). The 30-day survival for the three groups was similar but 1-year survival was higher in high-volume centres (80.8) compared with medium-volume centres (70.0%) and low-volume centres (61.9%). The risk of 1-year mortality in low-volume centres was higher compared with high-volume centres in adjusted analysis (hazard ratio 2.74, 95% confidence interval 1.61-4.68, P = 0.01).

Lowest volume centres have lowest survival and there exists a volume threshold at which better outcomes are achieved.